Integration of area efficient antennas for phased array or wafer scale array antenna applications

ABSTRACT

Package structures are provided for integrally packaging antennas with semiconductor RFIC (radio frequency integrated circuit) chips to form compact integrated radio/wireless communications systems that operate in the millimeter-wave and terahertz frequency ranges. For example, a package structure includes an RFIC chip, and an antenna package bonded to the RFIC chip. The antenna package includes a glass substrate, at least one planar antenna element formed on a first surface of the glass substrate, a ground plane formed on a second surface of the glass substrate, opposite the first surface, and an antenna feed line formed through the glass substrate and connected to the at least one planar antenna element. The antenna package is bonded to a surface of the RFIC chip using a layer of adhesive material.

TECHNICAL FIELD

The field generally relates to antenna package structures and, inparticular, to antenna package structures and techniques to implementlarge phased array antenna systems or 3D wafer scale antenna arraysystems for millimeter-wave and Terahertz (sub millimeter-wave)operating frequencies.

BACKGROUND

In general, RF (radio frequency) systems typically utilize some type ofantenna structure for wireless communication. For frequencies up to 60GHz, an antenna structure is designed separately from a radio frequencyintegrated circuit (RFIC) package, and then connected to the RFICpackage. In particular, with this technique, an antenna structure,whether a single antenna or an antenna array, can be connected to theRFIC package using cables with connectors or using bonding wires.

For millimeter-wave frequencies in a range of 60 GHz to 94 GHz, anantenna can be implemented in an antenna-in-package that includes andRFIC die, and one or more antenna structures and associated antenna feedlines, wherein the antenna structure is attached to the RFIC die. Thistechnique eliminates the need to use a bonding wire as the antenna feedline, thereby resulting in reduced power loss and reduced antennaimpedance mismatch due to the extra inductance from the bonding wire.With this design, the antenna-in-package is an RFIC package, as theantenna-in-package includes not only the antenna structure, but also allthe low frequency components, such as power plane, base band signallines, control lines, DC power supply line, etc. The antenna-in-packageis attached to an application board typically through BGA balls.

For operating frequencies above 94 GHz, however, it is not trivial todesign and manufacture antenna-in-package structures due to the lack ofavailability of proper antenna substrates and the limitations ofcurrently available processing technologies that do not afford therequisite manufacturing resolutions for such high-frequencyapplications. Furthermore, a standard interface between the antennapackage and the RFIC die (typically a flip-chip connection) producesmore than 1 dB signal attenuation at 94 GHz, minimizing the advantagesof antenna-in-package designs.

SUMMARY

In general, embodiments of the invention include package structures forintegrally packaging antennas with semiconductor RFIC chips to formcompact integrated radio/wireless communications systems that operate inthe millimeter-wave and terahertz frequency ranges. In one embodiment, apackage structure includes an RFIC chip, and an antenna package bondedto the RFIC chip. The antenna package includes a glass substrate, atleast one planar antenna element formed on a first surface of the glasssubstrate, a ground plane formed on a second surface of the glasssubstrate, opposite the first surface, and an antenna feed line formedthrough the glass substrate and connected to the at least one planarantenna element. The antenna package is bonded to a surface of the RFICchip using a layer of adhesive material.

Other embodiments of invention will be described in the followingdetailed description of embodiments, which is to be read in conjunctionwith the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic side view of a wireless communications packagestructure according to an embodiment of the invention.

FIG. 2 is a schematic side view of a wireless communications packagestructure according to another embodiment of the invention.

FIG. 3A is a schematic side view of a wireless communications packagestructure according to yet another embodiment of the invention.

FIG. 3B is a schematic top view of the wireless communications packagestructure of FIG. 3A, according to an embodiment of the invention.

FIG. 4 is a schematic side view of a wireless communications packagestructure according to another embodiment of the invention.

DETAILED DESCRIPTION

Embodiments of the invention will now be discussed in further detailwith regard to structures and methods for integrally packaging antennastructures with semiconductor RFIC chips to form compact integratedradio/wireless communications systems that operate in themillimeter-wave and terahertz frequency ranges. The exemplary antennapackage structures and techniques described herein are compatible withwafer-level 3D integration to enable the implementation of large phasedarray antenna systems or 3D wafer scale array antenna systems formillimeter-wave or terahertz operating frequencies.

It is to be understood that the various layers, structures, and regionsshown in the accompanying drawings are not drawn to scale, and that oneor more layers, structures, and regions of a type commonly used inintegrated antenna and chip packages may not be explicitly shown in agiven drawing. This does not imply that the layers, structures andregions not explicitly shown are omitted from the actual integrated chippackages. Moreover, the same or similar reference numbers usedthroughout the drawings are used to denote the same or similar features,elements, or structures, and thus, a detailed explanation of the same orsimilar features, elements, or structures will not be repeated for eachof the drawings.

FIG. 1 is a schematic side view of a wireless communications packagestructure according to an embodiment of the invention. In particular,FIG. 1 schematically illustrates a wireless communications device 100comprising an antenna package 110, a RFIC chip 120, and an applicationboard 130. The antenna package 110 comprises a glass substrate 112, aplanar antenna 114 formed on one side of the glass substrate 112, and aground plane 116 and contact pad 116A formed on an opposite side of theglass substrate 112. An antenna feed line 118 is formed through theglass substrate 112 providing an electrical connection between thecontact pad 116A and a feed point of the planar antenna 114. The contactpad 116A is formed to be electrically isolated from the ground plane116. The antenna package 110 is bonded to the RFIC chip 120 using alayer of adhesive material 140. In one embodiment, the layer of adhesivematerial 140 has a thickness in a range of about 1 μm to about 20 μm.

In general, the RFIC chip 120 comprises integrated circuitry 122, a BEOL(back end of line) structure 124, an insulating layer 126, and aplurality of metallic joint structures 128 and 129 (or micro vias). Inone embodiment of the invention, the RFIC chip 120 is formed using abulk SOI (silicon on insulator) substrate having a buried oxide (BOX)layer disposed between two layers of silicon wherein one layer ofsilicon (front side surface) comprises a thin silicon layer in whichactive devices are formed, and wherein the other layer of silicon (backside surface or substrate) is a relatively thick silicon layer that canbe utilized for various purposes as is known in the art.

In the embodiment of FIG. 1, the integrated circuitry 122 comprises aplurality of active circuit devices and other electronic components thatare formed in the front side (active surface) of the RFIC chip 120. Inparticular, for an SOI substrate embodiment, the integrated circuitry122 is formed in the thin silicon layer on the front side of the SOIsubstrate. The integrated circuitry 120 includes active devices andother components that are configured to implement, e.g., a receiver, atransmitter, or a transceiver circuit, and other active or passivecircuit elements that are commonly used to implement a wirelesscommunications system, an imager, or millimeter-wave/terahertz sensors.

Furthermore, for an SOI substrate embodiment, the insulating layer 126in FIG. 1 corresponds to the BOX layer of the SOI substrate. Theinsulating layer 126 may be formed of a silicon oxide material, such asSiO₂ (dielectric constant of 3.9) or other types of insulating ordielectric materials that are suitable for the given application. In oneembodiment, the insulating layer 126 is formed of SiO2 with a thicknessof about 10 nm to about 4 μm. In the illustrative embodiment of FIG. 1,it is assumed that the backside silicon layer of the SOI substrate iscompletely removed (via a grinding process and/or an etching/thinningprocess) before bonding the antenna package 110 to the backside of theRFIC chip 120 via the layer of adhesive material 140.

The BEOL structure 124 is formed on the front side of the RFIC chip 120to provide electrical connections between components of the integratedcircuitry 122. In general, the BEOL structure 124 comprises multiplelayers of metallization patterns 124A and insulating (dielectric)material 124B, as well as a plurality of bonding pads 124C. In oneembodiment, the BEOL structure 124 has a total thickness of about 5 μmto about 20 μm. The BEOL structure 124 can be built using well knownsemiconductor processing technologies and materials that are suitablefor the given application.

The metallization patterns 124A comprise inter-level contact pads,interconnect wires, and vias, which are used to form electricalconnections between components of the integrated circuitry 122. Theinsulating material 124B may be formed of layers of silicon oxidematerial, or other suitable dielectric materials with a dielectricconstant in a range of about 2 to about 3.9, for example. The metallicjoint structures 128 and 129 are metallic elements (micro via elements)that are formed (separate from, and subsequent to, the BEOL processing)to provide electrical connections between components of the antennapackage 110 and metallization patterns 124A of the BEOL structure 124.

Furthermore, the bonding pads 124C of the BEOL structure 124 include,for example, ground pads, DC power supply pads, I/O (input/output)signal pads, control signal pads, etc. The application board 130comprises a plurality of bonding pads 132 that are formed in alignmentwith corresponding ones of the bonding pads 124C of the RFIC chip 120.In the embodiment of FIG. 1, the RFIC chip 120 is flip-chip mounted tothe application board 130 using an array 150 of controlled collapse chipconnections (C4), or other known techniques. It is to be understood thatsome of the C4 connections may be non-electrical connections that merelyserve to physically bond the RFIC chip 120 to the application board 130,while other C4 connections may serve as bonding connections, as well aselectrical interface connections between the application board 130 andthe RFIC chip 120.

For instance, in the embodiment of FIG. 1, a C4 connection 152 isutilized in conjunction with the metallic joint 128, a portion of theBEOL metallization pattern, and the contact pads 124A and 124C, to forma ground connection between the ground plane 116 of the antenna package110 and a ground contact 132 on the application board 130. On the otherhand, a C4 connection 154 (and others) may simply be used to flip-chipbond the RFIC chip 120 to the application board 130, such that no wiringis connected to the associated bonding pads 124C and 132 and, thus, theC4 connection does not serve as an electrical connection. Moreover,other C4 connections 150 (not specifically shown in FIG. 1) providesupply voltage connections, I/O connections, control signal connections,etc., between the RFIC chip 120 and associated contact pads 132 on theapplication board 130.

In other embodiments of the invention, the RFIC chip 120 can beelectrically connected to the application board 130 using wire bonds, asis readily understood by one of ordinary skill in the art. For example,in one embodiment, the RFIC chip 120 can be designed with a largerfootprint (e.g., larger width) than the footprint of the antenna package110, such that the contact pads 124C of the BEOL structure 124 could beformed on the peripheral/perimeter region of the backside surface of theRFIC chip 120, which is not covered by the antenna package 110. In thisembodiment, the front side of the RFIC chip 120 could be bonded to theapplication board 130 using an adhesive material or some other standardbonding techniques, and wire bonds would be formed to make electricalconnections between the bonding pads 132 on the application board andthe bonding pads 124C that are exposed on the perimeter region of thebackside surface of the RFIC chip 120. In other embodiments, anelectrical interface can be implemented using a combination of C4connections and wire bonds, as is readily understood by one of ordinaryskill in the art.

As is readily understood by one of ordinary skill in the art, theapplication board 130 can be formed of one or more substrates comprisingone or more levels of metallization patterns and via structures to routethe I/O signals, control signals, and power supply signals to and fromthe RFIC chip 120 as needed. The application board 130 can be formed ofstandard FR4 material with copper metallization, or other suitablematerials commonly used to construct a standard PCB (printed circuitboard), for example.

In the embodiment of FIG. 1, the antenna package 110 is a structure thatcan be separately fabricated and then bonded to the RFIC chip 120. Theantenna package 110 can be fabricated from a metallized glass substrate,wherein the planar antenna 114 and ground plane 116 and contact pad 116Aare formed by patterning metal layers on opposing side of the glasssubstrate 112. The metallic patterns can be formed of copper or gold, orother types of metallic material suitable for the given application. Theglass substrate 112 can be formed of a glass material that is suitablefor the given application. In one embodiment, the glass substrate 112 isformed of a glass material having a dielectric constant ε of about 4.0.The antenna feed line 118 can be a TGV (through-glass-via) that isformed by etching or drilling a hole through the glass substrate 112,and then filling the through hole, or electroplating the walls of thethrough hole, with a metallic material such as copper.

The planar antenna 114 can be implemented using any suitable planarantenna structure that provides broadside radiation R as shown inFIG. 1. In one embodiment of the invention, the planar antenna 114comprises a planar patch radiating element having a resonant length in arange from about one-quarter wavelength to about one-half wavelength.The contact point of the antenna feed line 118 to the planar antenna 114is selected so that the antenna impedance is matched to 50 Ohms, whichis standard for most RF transceivers.

Depending on the type of planar antenna used, the ground plane 116operates as an antenna ground plane (e.g., for microstrip-type antennastructures) as well as a reflector element to reflect radiation awayfrom the RFIC chip 120. In other embodiments in which the planar antenna114 can operate as a radiating element without the need for an antennaground plane, the ground plane 116 serves to reflect radiation away fromthe RFIC chip 120.

The operating frequency and other performance characteristics of theantenna package 110 will vary based on, e.g., the dimensions of theplanar antenna 114 and the glass substrate 112, and the dielectricconstant of the glass material used to form the glass substrate 112. Forexample, for a planar patch antenna, a length of the patch antenna willdetermine an operating frequency and other performance characteristicsof the antenna. Typically, the length of a planar patch antenna is in arange of about ¼-wavelength to about ½-wavelength. For a phased arrayantenna application (e.g., FIG. 2) with multiple patch antennas forexample, the distance (pitch) between each patch antenna in the phasedarray is equal to about λ/2.

Moreover, the distance between the planar antenna 114 and the groundplane 116 (i.e., the thickness of the glass substrate 112) can be variedto trade-off antenna bandwidth and efficiency. The antenna bandwidth canbe improved by increasing the distance between the planar patch antenna114 and ground plane 116, at the cost of decreased antenna efficiency.In one embodiment, the glass substrate 112 can have a thickness in arange from about 50 μm to about 750 μm, which provides a 12% targetbandwidth an over an operating frequency range from about 10 GHz toabout 150 GHz.

With regard to the antenna feed line 118, the minimum width of the TGVis limited by the aspect ratio that can be achieved with the etching ordrilling process used to form a through hole in the glass substrate 112.Typically an aspect ratio of 2 or 10 to 1 can be achieved. Therefore,for a glass substrate with a thickness of 50 μm, a minimum width of 25μm to 5 μm can be achieved.

With regard to the thickness of the metallization, the metal thicknesscan be derived by computing the skin depth given by:

${\delta = \sqrt{\frac{2\rho}{2\pi \; f\; \mu}}},$

where ρ is the metal conductivity and μ is the permittivity. For copperat 60 GHz, the skin depth is 0.27 μm. To minimize ohmic losses, themetallization should have a thickness of at least 5 skin depths.Therefore, for a 60 GHz operating frequency, the thickness of the coppermetallization should be at least 1.35 μm.

In one embodiment of the invention, the wireless communications device100 of FIG. 1 is fabricated as follows. As noted above, the antennapackage 110 and RFIC chip 120 are fabricated separately, and then bondedtogether using adhesive material. The RFIC chip 120 is fabricated usingstandard CMOS or other semiconductor processing technologies. Forexample, starting with an SOI substrate, FEOL (front end of line)processing techniques are utilized to form the integrated circuitry 122on the front side silicon layer of the SOI substrate, followed by BEOLprocessing techniques to form the BEOL structure 124.

The SOI substrate is then bonded face down to a handler substrate (e.g.,glass carrier) using a polyimide adhesive, for example. Then, a backsideetching or grinding process is performed to remove the backside bulksilicon layer from the SOI substrate. With this process, the bulksilicon layer is completely removed down to the BOX layer (e.g., theinsulating layer 126 in FIG. 1). Following the backside etch, a processis performed to form the metallic joints 128 and 129 with the etched SOIsubstrate still attached to the handler substrate.

In particular, in one embodiment of the invention, the metallic joints128 and 129 are formed as follows. Initially, a layer of photoresistmaterial is deposited on the BOX layer and patterned to form openings inthe photoresist in regions of the backside surface where via holes areto be etched and subsequently filled with metallic material (e.g.,copper) to form the metallic joints 128, 129. The patterned photoresistlayer is then used as a mask to perform an anisotropic etch process toetch the BOX layer (insulating layer 126) and the BEOL insulatingmaterial 124B down to contact pads that are formed as part of the BEOLmetallization 124A.

Following the etch process, the photoresist pattern is removed usingstandard techniques, and a thin conformal seed layer is deposited toline the etched via holes. The thin conformal seed layer can be a thincopper layer. Following deposition of the seed layer, a photoresistmaterial is deposited and patterned to form a second photoresist patternthat exposes the via holes lined with the seed layer. A copper fillprocess is then performed to fill the exposed via holes with coppermaterial using the seed layer as a nucleating layer for the depositionprocess. In one embodiment, the copper fill process can be implementedusing an electroplating process wherein the seed layer serves as ananode/cathode for the electroplating process. With this process, thesecond photoresist pattern covers the backside region of the SOIsubstrate so that copper is only deposited in the via holes exposed bythe second photoresist pattern.

Following the copper fill process, the second photoresist pattern isremoved, resulting in the completed RFIC chip 120 with exposed portionsof the metallic joints 128 and 129 on the backside of the RFIC chip 120.As this stage of fabrication, the front side of the RFIC chip 120remains attached to the handler substrate. Then, the separately formedantenna package 110 is bonded to the etched backside of the RFIC chip120, wherein copper bonding process is performed to bond the exposedsurfaces of the metallic joints 128, 129 to desired contact points ofthe metallization (e.g., ground plane 116, contact pad 116A, FIG. 1) onthe bottom surface of the glass substrate 112.

Furthermore, as part of this bonding step, a layer of adhesive material(e.g., adhesive layer 140, FIG. 1) is formed on the bottom surface ofthe glass substrate 112, which further serves to bond the antennapackage 110 to the backside of the RFIC chip 120. In one embodiment, thelayer of adhesive material includes a polyimide layer with a thicknessof 2-3 μm, for example.

After the antenna package 110 is bonded to the backside of the RFIC chip120, the handler substrate is removed from the front side of the RFICchip 120 using a standard release process. For example, a laser releaseprocess can be performed by irradiating the adhesive layer (which bondsthe handler substrate to the RFIC chip 120) through the handler (glass)substrate, to thereby laser ablate the adhesive layer and release thehandler substrate from the front side of the RFIC chip 120. A cleaningprocess is then performed to remove any remaining residue from the frontside of the RFIC chip 120. Thereafter, the RFIC chip 120 (with theantenna package 110 mounted on the backside thereof) is bonded to theapplication board 130 using, e.g., C4 connections, as discussed above.Again, in other embodiments as discussed above, wire bond connectionscan be utilized (either alone or in combination with C4 connections) toprovide electrical connections between the RFIC chip 120 and theapplication board 130.

The embodiment of FIG. 1 illustrates an antenna package 110 with asingle glass substrate 112 and one antenna structure for an SOIimplementation. In other embodiments of the invention, antennastructures that utilize multiple stacked glass substrates can beimplemented as well. For example, such antenna structures includestacked patch antennas, L-probe fed patch antennas, grid antennas,dipole antennas, etc. By way of specific example, in a stacked patchantenna implementation, an antenna package comprises a first glasssubstrate and a second glass substrate bonded together to form stackedstructure, wherein the first glass substrate comprises a first patchradiator element, and wherein the second glass substrate comprises asecond patch radiator element. The second patch radiator element can befed by an antenna feed line (such as shown in FIG. 1), whereas the firstpatch radiator element (disposed over the second patch radiator element)can be capacitively feed by the second patch radiator element.

Moreover, in other embodiments of the invention, an antenna package canbe fabricated with multiple antenna radiating elements to provide aphased array antenna system. For example, FIG. 2 is a schematic sideview of a wireless communications package structure according to anotherembodiment of the invention, which provides a phased-array antennastructure for an SOI implementation. In particular, FIG. 2 schematicallyillustrates a wireless communications device 200 comprising multiplepackage structures 202A, 202B, and 202C bonded to an application board130 using an array of C4 connections 150.

In the embodiment of FIG. 2, each package structure 202A, 202B, and 202Ccomprises a respective antenna package 110A, 110B, and 110C, bonded to abackside of a respective RFIC chip 120A, 120B and 120C. Each packagestructure 202A, 202B, and 202C is conceptually similar in design to thepackage structure (antenna package 110 and RFIC chip 120) discussedabove with reference to FIG. 1. However, in the embodiment of FIG. 2,each package structure 202A, 202B, and 202C is a separate package thatis bonded to the application board 130 so as to maintain antennaelements 114-1, 114-2, 114-3 and 114-4 at half-wavelength spacing. Theembodiment of FIG. 2 is useful for a large antenna array SOIimplementation by allowing the tiling of separate chips with halfwavelength spacing. While some package structures (e.g., 202A and 202C)are formed with one antenna element (e.g., 114-1 and 114-4), otherpackage structures (e.g., 202B) are formed with multiple antennaelements (e.g., 114-2 and 114-3). Each package structure 202A, 202B and202C can be fabricated using the techniques discussed above withreference to the exemplary embodiment of FIG. 1.

FIGS. 3A and 3B schematically illustrate a communications packagestructure according to yet another embodiment of the invention. Inparticular, FIG. 3B is a schematic top view of a wireless communicationsdevice 300, while FIG. 3A is a schematic side view of the wirelesscommunications device 300 taken along line 3A-3A in FIG. 3B. Theembodiment of the wireless communications device 300 in FIGS. 3A/3B issimilar to the embodiment of the wireless communications device 200 ofFIG. 2, except that the embodiment of FIGS. 3A/3B provides a 3D SOIwafer scale implementation, at millimeter-wave frequencies, for a verylarge phased-array antenna application.

In particular, as shown in FIGS. 3A/3B, an antenna package 310 comprisesan array of planar antennas (e.g., antennas 114-1, 114-2, 114-3, 114-4 .. . , 114-n) that are formed on one side of a single glass wafer 312.The wafer scale antenna package 310 is bonded to a backside surface ofan SOI wafer 320 comprising active RFIC integrated circuitry and BEOLstructures, as needed, to operate the array of antennas 114-1, 114-2,114-3, 114-4 . . . , 114-n as a phased-array antenna system, usingtechniques known to those of ordinary skill in the art.

FIG. 4 is a schematic side view of a wireless communications packagestructure according to another embodiment of the invention. Inparticular, FIG. 4 schematically illustrates a wireless communicationsdevice 400 which is similar to the wireless communications device 100 ofFIG. 1, except that in the exemplary embodiment of FIG. 4, the antennapackage 110 is bonded to a front side surface of an RFIC chip 420.

In particular, as shown in FIG. 4, the RFIC chip 420 comprisesintegrated circuitry 422, a BEOL structure 424, and a bulk silicon layer426. Although not specifically shown, in an SOI embodiment, the siliconsubstrate 426 may comprise a BOX layer, wherein the integrated circuitry422 is formed in a thin layer of silicon on top of the BOX layer. TheBEOL structure 424, which is formed on the front side of the RFIC chip420, comprises multiple layers of metallization patterns 424A embeddedin insulating (dielectric) material 424B, to provide electricalconnections between components of the integrated circuitry 422.

In the embodiment of FIG. 4, the antenna package 110 is bonded to thefront side of the RFIC chip 420 using the adhesive layer 140, whereasthe backside of the RFIC chip 420 is bonded to the application board 130using an array of C4 connections 150. As further depicted in FIG. 4, thebulk silicon layer 426 comprises a plurality of TSVs(through-silicon-vias) 428 to provide electrical connections betweencertain points of the metallization pattern 424A and bonding pads 430formed on bottom surface of the bulk silicon layer 426 (i.e., on thebackside of the RFIC chip 420). The through-silicon-vias 428 can befabricated using well known techniques. In other embodiments of theinvention, wire bonds can be utilized either alone, or in combinationwith C4 connections, to provide electrical connections between the RFICchip 420 and the application board 130.

In another embodiment of the invention, similar to the embodimentsdiscussed above with reference to FIGS. 2 and 3A/3B, a large phasedarray antenna system or wafer scale antenna array can be designed basedon the package structure of FIG. 4. In such embodiments, the RFIC chips120A, 120B and 120C (FIG. 2) and RFIC chip 320 (FIGS. 3A/3B) would bereplaced with an RFIC chip having a structure similar to that depictedin FIG. 4, wherein multiple RFIC chips or an RFIC wafer would bebackside mounted to the application board 130, with antenna packages oran antenna wafer bonded to the front side of the RFIC chip(s).

Those of ordinary skill in the art will readily appreciate the variousadvantages associated with integrated chip/antenna package structuresaccording to embodiments of the invention. For instance, the use of thelow-loss glass substrates to form antenna package structures enables therealization of high-efficient antenna designs that are compatible foruse with high-resistivity bulk, SOI, or SOG (silicon on glass) Sitechnologies, while using standard bonding techniques to form thepackage structures. These standard processing techniques enable antennasto be integrally packaged with IC chips such as transceiver chips,thereby providing compact designs with very low loss between thetransceiver and the antenna. The use of semiconductor fabricationtechnologies (as compared to PCB technology) allow the design ofhigher-precision metallization geometries compatible with millimeterwave and terahertz operating frequencies.

Moreover, various types of antenna designs can be implemented asdiscussed above for single antenna or phased-array antenna applications.The embodiments discussed herein are compatible with wafer scale levelfabrication and integration, thereby enabling ease of manufacture oflarge phase array antenna structures. Moreover, multiple wafer levelintegration can be tiled (e.g., FIG. 2) to readily increase a number ofantenna for use in phase-array antenna applications using a multitude ofdifferent chips integrated on a given carrier or application board toimplement a phase-array antenna.

It is to be further understood that the antenna package structuresillustrated herein can extended or varied depending on the application,e.g., antenna structure, I/O routing requirements, power and groundplane requirements, etc. Those of ordinary skill in the art readilyunderstand that the antenna performance parameters such as antennaradiation efficiency and bandwidth and operating resonant frequency willvary depending on the dielectric constant, loss tangent, and thicknessof the dielectric/insulating materials that form the substrate layers.Moreover, the size and structure of the various radiating elements ofthe antennas shown in drawings will determine the resonant frequency ofthe antenna, as is well understood to those of ordinary skill in theart.

Although embodiments have been described herein with reference to theaccompanying drawings for purposes of illustration, it is to beunderstood that the present invention is not limited to those preciseembodiments, and that various other changes and modifications may beaffected herein by one skilled in the art without departing from thescope of the invention.

We claim:
 1. A package structure, comprising: an RFIC (radio frequency integrated circuit) chip; and an antenna package comprising a glass substrate, at least one planar antenna element formed on a first surface of the glass substrate, a ground plane formed on a second surface of the glass substrate, opposite the first surface, and an antenna feed line formed through the glass substrate and connected to the at least one planar antenna element, wherein the antenna package is bonded to a surface of the RFIC chip using a layer of adhesive material.
 2. The package structure of claim 1, further comprising an electrical interface between the antenna package and the RFIC chip, wherein the electrical interface comprises micro via joints.
 3. The package structure of claim 2, wherein the micro via joints are formed within a BEOL (back end of line) structure of the RFIC chip, and wherein the micro via joints provide electrical connections between wiring of the BEOL structure and metallization on the second surface of the glass substrate.
 4. The package structure of claim 1, wherein the second surface of the antenna package is bonded to a backside surface of the RFIC chip.
 5. The package structure of claim 4, wherein the RFIC chip comprises a silicon-on insulator (SOI) substrate, wherein the SOI substrate comprises a silicon layer in which active devices are formed, and a buried insulating layer, wherein the backside surface of the RFIC chip is etched to expose the buried insulating layer, and wherein the antenna package is bonded to the buried insulating layer of the SOI substrate.
 6. The package structure of claim 1, wherein the second surface of the antenna package is bonded to a front side surface of the RFIC chip.
 7. The package structure of claim 1, wherein the at least one planar antenna element comprises a plurality of planar antenna elements forming an antenna array.
 8. The package structure of claim 1, wherein the glass substrate is a glass wafer, and wherein the RFIC chip is an element of a semiconductor wafer comprising multiple chips, wherein the glass wafer and semiconductor wafer are bonded together to form an integral package.
 9. An antenna package, comprising: a glass wafer having a first surface and a second surface, opposite the first surface; a plurality of planar antenna elements patterned on the first surface of the glass wafer forming an array of antenna radiating elements; a ground plane formed on the second surface of the glass wafer; and a plurality of antenna feed lines formed through the glass wafer from the first surface to the second surface, wherein the antenna feed lines are connected to corresponding ones of the planar antenna elements patterned on the first surface of the glass wafer.
 10. The antenna package of claim 9, wherein the glass wafer is a glass material having a dielectric constant of about 4.0.
 11. A wireless communications device, comprising: an RFIC (radio frequency integrated circuit) chip; and an antenna package comprising a glass substrate, at least one planar antenna element formed on a first surface of the glass substrate, a ground plane formed on a second surface of the glass substrate, opposite the first surface, and an antenna feed line formed through the glass substrate and connected to the at least one planar antenna element, wherein the antenna package is bonded to a surface of the RFIC chip using a layer of adhesive material; and an application board, wherein the RFIC chip is mounted to the application board.
 12. The wireless communications device 11, further comprising an electrical interface between the antenna package and the RFIC chip, wherein the electrical interface comprises micro via joints.
 13. The wireless communications device of claim 12, wherein the micro via joints are formed within a BEOL (back end of line) structure of the RFIC chip, and wherein the micro via joints provide electrical connections between wiring of the BEOL structure and metallization on the second surface of the glass substrate.
 14. The wireless communications device of claim 11, wherein the second surface of the antenna package is bonded to a backside surface of the RFIC chip, wherein the RFIC chip comprises a silicon-on insulator (SOI) substrate, wherein the SOI substrate comprises a silicon layer in which active devices are formed, and a buried insulating layer, wherein the backside surface of the RFIC chip is etched to expose the buried insulating layer, and wherein the antenna package is bonded to the buried insulating layer of the SOI substrate.
 15. The wireless communications device of claim 11, wherein the second surface of the antenna package is bonded to a front side surface of the RFIC chip.
 16. The wireless communications device of claim 11, wherein the at least one planar antenna element comprises a plurality of planar antenna elements forming an antenna array.
 17. The wireless communications device of claim 11, wherein the glass substrate is a glass wafer, and wherein the RFIC chip is an element of a semiconductor wafer comprising multiple chips, wherein the glass wafer and semiconductor wafer are bonded together to foam an integral package.
 18. The wireless communications device of claim 11, wherein the RFIC chip is bonded to the application board using an array of C4 solder ball connections.
 19. The wireless communications device of claim 11, wherein the glass substrate is a glass material having a dielectric constant of about 4.0.
 20. The wireless communication device of claim 11, wherein the wireless communications device is configured to operate at a millimeter wave frequency range or higher. 